Change generating version

* Always generate version include files at compile time
* Replace header file src/trojita-version.h with plain string in src/version
* Generated file contains #define preprocesor macros instead C char array, so it can be used also in windows resource file
* Generate also NSI include file, which has different syntax as C preprocessor and C char array
* Windows resources using four 16bit integers as version number, so cmake will prepare these numbers from version string

REVIEW: 112371
Add Windows NSIS Installer

* using Modern UI 2 interface
* using named mutex to allow run only one installer instance
* support both 32 and 64 bit systems, show error message when 64 bit installer is started on 32 bit machine
* support upgrading via removing previous installation
* optionally can create startup and desktop shortcuts
* creating uninstaller and adding it to add/remove programs menu registry

* only trojita executable (without any DLL libraries) is included in installer

REVIEW: 112224
Add support for MinGW RC compiler and full windows resource info

This includes icon, name, version, description, file type, license and homepage.

REVIEW: 112372
CMake: MinGW compiler is tested and working